Panel made of a highly insulated electrothermal fabric

ABSTRACT

Panel ( 10 ) for generating and diffusing heat obtained from a heat-radiating board ( 30 ) comprising one or more pieces of electrothermal fabric, with strips of fibreglass laid side by side to form the warp, the weft ( 50 ) consisting of a continuous copper wire ( 51 ), small in diameter and of considerable length, coated with insulating material, that extends serpentinewise passing alternatively above and below the strips of fibreglass, said board ( 30 ) being completed by intermediate and external layers ( 35, 36 ) of epoxidic thermoadhesive material and clad on both surfaces with sheets of micanite ( 31, 32 ), so that on connecting the ends of the wire ( 51 ) forming the weft ( 50 ) to a source of electric current, boring holes ( 65, 66 ) using means, that may be a laser beam, on the thermoadhesive layer ( 35, 36 ) covering the weft ( 50 ), this latter converts electric energy into thermal energy.

BACKGROUND OF THE INVENTION

The invention concerns means for generating heat for indoor use byelectric current.

There are innumerable systems and means for generating heat for thispurpose by electricity.

These systems are based on the use of highly resistant materials which,if electric current is passed through them, reach very high temperaturesat a great concentration of heat.

Such heat is nearly always much more than the environment would requireand must therefore be diffused by means of complex and costly devicesspecially made for the purpose.

The high temperatures in the head conductors render necessary certainmeans of support made of special and fragile materials such as ceramicand the like, and complex insulation and coating structures.

These structures rapidly wear out because of the high temperatures theyhave to carry.

Thermal efficiency, especially if compared with other means of heatingby fuels, is very low because of the high thermal difference between theelectric resistances and room temperature

The means of heating are also bulky and, from the practical andaesthetic points of view, are difficult to combine with the furniture.

SUMMARY OF THE INVENTION

The above invention solves these problems, offering a means of electricheat that is flat, small in size and light in weight, as well as beinghighly insulated, as will be explained below.

Subject of the disclosure is a panel for generation and diffusion ofheat having on it an electrothermal fabric, and a board of heatradiating material consisting of one or more pieces of said fabric. Saidfabric presents continuous weft wires, coated with highly insulatingmaterial and having electric contacts at their ends.

Intermediate and external layers of thermoadhesive material complete theboard, covered on both sides by a mica-based material.

By connecting the electric contacts to a source of electricity, the weftwires convert electric energy into thermal energy and, through thesheets of mica-based material, radiate heat throughout the environment.

The warp threads of the pieces of fabric consist of thin parallelthreads of fibre glass laid side by side.

The weft wires run continuously from a first corner on a first side ofthe piece of fabric, crosswise to the weft wires, first passing above afirst face of the first strip, above the second face of the next strip,above the first face of the strip next again, and so on till it reachesthe opposite side of the piece.

From there, after making a bend at 180°, said wire returns to the firstside, closely aligned the whole previously inserted length.

From this first side, after making a another 180° bend, said wirereturns to the opposite side of the piece passing above the second faceof the first strip, above the first face of the next strip, above thesecond face of the strip next again, and so on until the whole weftweave of the piece has been completed.

This way of laying of the conductor in lengths placed side by side,passed through by electric current in the opposite direction of flow,eliminates the electric fields.

Advantageously, the highly conductive weft wire is of copper.

The electrical contacts are connected at the two ends of the wire thatforms the weft weave, to be used to convert electric current intothermal energy, creating, by suitable means, a hole in thethermo-adhesive layer that covers one face of the electrothermic sheet.

This hole also passes through the insulation of the wire, a weld, orequivalent means, being put into said hole to connect said wire to anelectric contact.

The hole may be produced by a grinder, by sanding or by a laser beam.

Being laser, said beam penetrates the insulating lining on the metalwire of the weft weave, but is repelled by the metal itself.

The heat radiating plate is mounted inside a protective frame.

This frame consists of two halves, of a constant section at an angle of90°, shape and internal dimensions corresponding to the externaldimensions and shape of the main parts of the panel, and being providedwith means for a stable assembly.

The external dimensions of one half of the frame correspond to theinternal dimensions of the other half.

The shape of the panel is preferably square.

The external sheets of the panel are of micanite. This consists of smallflakes of mica glued onto paper or cloth.

In another execution the external sheets are of micarta. The supportingmaterial for micarta is a fabric of fibreglass which can be impregnatedwith polyester or epoxy resins.

A thermal sensor is placed centrally on the heat radiating plate: itscontacts can be connected to the two ends of a break in the continuouswire that forms the weft.

This sensor breaks the electric circuit of the heat-radiating plate whenits temperature exceeds a certain level.

In one type of execution the heat-radiating sheet comprises twosuperimposed pieces of electrothermal fabric with a thermoadhesive layerin between and at the ends.

The weft wires of the two pieces of superimposed fabric can be connectedin parallel or in series.

The thermoadhesive material is preferably epoxidic.

The face of the heat-radiating board that will be on view can be coveredwith a sheet of decorative melamine.

The invention offers evident advantages.

In view of the nature of this mineral, the mica-based sheets, such amicanite, micarta and the like, ensure maximum electrical insulation andat the same time maximum diffusion of the heat on account of their beingso thin, even only a few tenths of a millimetre thick, while at the sametime ensuring good mechanical strength and maximum electricalinsulation.

Comprising as it does one or more pieces of thermoelectric fabric withthe weft weave formed of a highly conductive wire, the heat radiatingplate also ensures maximum thermal efficiency, even though it is sothin, bulk and weight as well being minimum.

The width and length of the panel can be decided as preferred, to makeit useful for a variety of purposes.

The possibility of applying a decorative sheet to the surface on view,or even of decorating the face of the mica-based material, helps to makethe panel suitable for any environment and for placing in any position

Characteristics and purposes of the disclosure will be made stillclearer by the following examples of its execution illustrated bydiagrammatically drawn figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Panel with a heat-radiating board comprising a piece ofelectrothermal fabric, with surrounding frame, perspective.

FIG. 2 Cross section of the panel.

FIG. 3 An exploded view of the panel.

FIG. 4 The heat-radiating board showing its component parts,perspective.

FIG. 5 Detail of the electrothermal fabric comprised in the heatradiating board.

FIG. 6 Detail of the heat-radiating board, a cross section.

FIG. 7 As above with a laser making a blind hole.

FIG. 8 As above, with an electric contact being welded into the blindhole.

FIG. 9 Heat-radiating board with two pieces of electrothermal fabric,perspective.

FIG. 10. Cross section of the board in FIG. 9.

FIG. 11. The board in FIG. 9 with a laser beam making two blind holesfacing in opposite directions.

FIG. 12. As above with an electric contact being welded into the blindholes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The square panel 10 comprises the electrothermal sheet 30 protected bythe frame 20 consisting of the two halves 21 and 22.

The half-frame 21 presents a front 23 and edge 26 at 90°.

The half frame 22 presents a front 27 and edge 28, also at 90°.

The external dimensions of the half-frame 22 correspond to the internaldimensions of the other half 21 so that one fits firmly into the otherto form a stable frame.

The heat-radiating board 30 is formed of a place 40 of special fabricplaced between two layers, 35 and 36, of epoxidic thermoadhesivematerial and is clad on the two outer faces by pieces 31 and 32 ofmicanite.

A decorative sheet 33 of melamine paper is laid on the surface to remainon view.

The piece 40 of special fabric (FIG. 5) presents a warp 43-45 and a weft50.

The warp is formed of parallel strips 43-45 laid side by side, eachstrip being formed of fibreglass threads 46.

The weft 50 is formed of a continuous copper wire 51 coated withinsulating paint 52.

The copper wire is inserted at one end, for example 55 (on the left lowdown in FIG. 5), of one side of the piece 40, crosswise to thefibreglass strips 43-45, passing alternatively on the first, on thesecond, on the first face, and so on, of the successive strips 43-45,emerging at the second end 56 (above, on the left, in the figure) of theopposite side of the piece, and after making an 180°-bend 57, returnsinto the piece alongside the first already mentioned length of wire soreturning to the first side 55.

After making another 180° bend 58, it once more returns to the fabric,at a distance from the first length corresponding substantially to thewidth of the strips 43-45 as far as the opposite side of the piece 40,and so on to complete the weft as indicated, for example, by the end 53of the wire.

It will therefore be seen that by joining electric contacts at any twopoints in the weft, obviously first removing the coating 52 on thecopper wire 51, an electric circuit can be closed on the length of wirebetween said points so generating heat by converting electric energyinto thermal energy.

FIGS. 6-8 show the method followed to do this.

The holes 65, 66 are made by the laser beam 60 on the surface of thethermoadhesive layer 36. Said beam perforates the thermoadhesive layer36 and the coating 52 on the copper wire 51.

The electric contacts 75, 76 can therefore be connected at the two endsof the length of copper wire between the two holes, by welds 70, 71 madein the holes 65, 66.

Said contacts 75, 76 are connected to the electric wires 15, 16 thatbring in mains electricity through the cable 17 and plug 18.

FIG. 9 shows a heat-radiating board 80 comprising two pieces 40, 90 ofspecial fabric with an intermediate layer 81 and two outer layers 82, 83of epoxidic thermoadhesive material.

The board is clad on its two surfaces by pieces of micanite 31, 32.

FIGS. 9-12 show how mains electricity can be used to feed both the wefts50 and 91 of copper wire in the pieces of fabric 40 and 90 by connectingthe wires 15, 16 in the cable 17 to contacts 108, 109. These contactsare fixed to said wefts 50 and 91 by welds 106, 107 (FIGS. 9 and 12)made inside the pairs of holes 95 and 97 in the two faces 85 and 86 ofthe plate 80 by laser beams 100 and 101 at the ends of said wefts 50 and91.

By making further holes 96 and 98 (FIG. 9) at the other ends of wefts50, 91, and creating an electric bridge 105 to connect said ends bywelds 102 and 103 made in said holes, wefts 50 and 91 becomeelectrically connected in series.

FIG. 9 shows, practically in the centre of the upper surface of theheat-radiating board 80, a discoid sensor 120 with switch whose contactsare connected to the two separated ends of the copper warp below saidupper surface.

It follows that, when the temperature of the heat-radiating boardexceeds a certain pre-set value in the sensor, the switch in said sensorautomatically opens thus opening the electric circuit and preventingfurther generation of heat until the temperature has fallen to thepre-set level.

As will be seen in FIG. 3, the electric cable 17, with plug 18, passesthrough the two opposite cavities, respectively 12 in the half frame 21and 13 in the half frame 22.

On completing assembly, the panel appears as in FIG. 1.

When the plug 18 is plugged in to an electric socket, the copper weftwires 50 and 91 in the pieces ot thermoelectric fabric 40 and 80,receive current and heat up to a moderate temperature of about 100° C,the heat so generated, on passing through the micanite, is radiatedoutwards from the panel to the environment as shown by the arrrows 11.

The surface of the .panel on view shows the decorative sheet of melamine33.

Micanite is well known to be an insulating material consisting of astiff or flexible sheet made from flakes of mica, of muscovite inparticular.

To give it greater mechanical strength, micanite sheets may be made withthe mica flakes glued onto paper or cloth. As an alternative, micartamay be used, this consisting of tiny flakes of pure mica mixed to form apaste without glue, then compressed and felted.

Micarta may be given a cloth or glass base or be impregnated withpolyester and epoxy resins.

As the case may require, the sheets of micanite shown in the figures cantherefore be replaced by sheets of micarta and the like.

1. A method for formation of a panel for generating and diffusing heat,comprising the steps of: providing a board having one or two pieces offabric with a weft of continuously highly-conductive metal wire coatedwith insulating material and with a warp formed of parallel strips laidside-by-side, wherein said parallel strips are formed of fiberglassthreads placed side-by-side; forming intermediate and external layers ofthermal adhesive epoxy material in relation to the pieces of fabric;providing first electrical contacts at a short distance from ends of themetal wire, wherein said first electrical contacts are connected to asource of electric current; forming holes in the insulating layer ofthermoadhesive epoxy material that coats the pieces of fabric, at twoends of the metal wire weft, using laser beams, which, by their nature,are repelled by the metal of the wire; connecting the first electricalcontacts to the ends of the metal wire of the waft by welds inserted insaid holes; extending the wire constituting the waft continuously from afirst corner on a first side of the piece of fabric, crosswise to thewarp strips passing over a first face of a first strip, over a secondface of a next strip, over a first face of a strip next again and so onto reach an opposite side of the place and from there, after marking abend at 180°, returning said wire toward the first side closely alignedalone a hole of a previously inserted length and from the first side sothat said wire makes a bend at 180° and returns towards the oppositeside of the pipe passing over a second face of the first strip, over afirst face of the next strip, over a second face of the strip next againand so on to complete a whole weft of the piece, providing an effect ofaligning the lengths of a conductive wire through which electric currentpasses on an opposite direction of flow, being to eliminate harmfulelectric field.